From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH 1/1] use USER_DS in vhost_worker thread Date: Tue, 26 Jun 2012 14:42:26 +0300 Message-ID: <20120626114226.GC13618@redhat.com> References: <1340708398-17965-1-git-send-email-borntraeger@de.ibm.com> <1340708398-17965-2-git-send-email-borntraeger@de.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm@vger.kernel.org, netdev@vger.kernel.org, Jens Freimann To: Christian Borntraeger Return-path: Content-Disposition: inline In-Reply-To: <1340708398-17965-2-git-send-email-borntraeger@de.ibm.com> Sender: kvm-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Tue, Jun 26, 2012 at 12:59:58PM +0200, Christian Borntraeger wrote: > From: Jens Freimann > > On some architectures address spaces are set up in a way that this is > not necessary to work properly but on some others (like s390) it is. > Make sure we operate on the user address space to allow copy_xxx_user() > from the vhost_worker() thread by setting it explicitly before calling > use_mm() and revert it after unuse_mm(). > > Signed-off-by: Jens Freimann > Signed-off-by: Christian Borntraeger Acked-by: Michael S. Tsirkin Dave, can you queue this up for 3.5 please? Thanks. > --- > drivers/vhost/vhost.c | 3 +++ > 1 files changed, 3 insertions(+), 0 deletions(-) > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index 94dbd25..112156f 100644 > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -191,7 +191,9 @@ static int vhost_worker(void *data) > struct vhost_dev *dev = data; > struct vhost_work *work = NULL; > unsigned uninitialized_var(seq); > + mm_segment_t oldfs = get_fs(); > > + set_fs(USER_DS); > use_mm(dev->mm); > > for (;;) { > @@ -229,6 +231,7 @@ static int vhost_worker(void *data) > > } > unuse_mm(dev->mm); > + set_fs(oldfs); > return 0; > } > > -- > 1.7.0.4